The present invention relates to tiltable steering column assemblies for motor vehicles, and more particularly to a rotary tilt mechanism having an improved locking mechanism.
Vehicle steering columns are often provided with a tiltable component that enables the steering wheel to be set at varying degrees of tilt, according to the desires and needs of different persons that might have occasion to drive a vehicle. Typically a manually operable lock mechanism is provided for retaining the steering wheel component in selected positions of tilt adjustment.
In one conventional rotary tilt mechanism an externally threaded rod is provided including pivot connections incorporated on opposite ends. A sleeve encircles the rod and is biased into a locking relationship with the rod by a biasing member. A lever is incorporated on the steering column in which the driver may actuate to overcome the bias. Actuation of the lever allows the rod to move into an unlocked position whereby the rod may slidably translate within the sleeve toward a desired position of tilt. Once the steering wheel is pivoted into the desired position, the lever is disengaged and the sleeve is biased into a locked relationship with the rod.
The biasing member conventionally is coupled on one end to an outer portion of the sleeve and on the other end to a pivot shaft. The pivot shaft transversely extends through passages incorporated on the sleeve and rod and operably connects to a lower stationary column member. In such a configuration wherein the biasing member is coupled to the pivot shaft, undesirable loads may be transferred to the passage walls formed on the sleeve and rod. Continued loads on the passage walls may encourage premature fatigue on the rod and sleeve.
Generally, assembly of such a rotary tilt mechanism includes rotating the rod and sleeve against the bias to a position in which an axial slot formed on the rod is aligned with a transverse slot formed in the sleeve to create a mounting passage. Next, a shipping pin or xe2x80x9cdummy pinxe2x80x9d is disposed through the mounting passage to preclude the biasing member from rotating the rod and sleeve out of position. When the rotary tilt mechanism is prepared for installation in a vehicle, a pivot pin is inserted into the mounting passage thereby displacing the shipping pin from the mechanism.
The rotary tilt mechanism of the present invention provides a configuration which minimizes loads transferred onto the passage walls while providing other improvements which increase the longevity and overall robustness of the mechanism.
The present invention provides an articulated, tiltable steering column including an upper steering wheel column member, and a lower stationary steering column member, and a pivot connection between the upper and lower column members, whereby a steering wheel can be tiltably adjusted around the pivot connection to selected positions of adjustment. A locking mechanism retains the column members in selected positions of adjustment. The locking mechanism further includes a rod disposed between the column members. The rod is received by and slidable along a longitudinal axis within a sleeve. The rod and sleeve include a passage formed therein for receiving a shaft. A collar is journalled around the sleeve including diametrically opposed bores for receiving the shaft. A biasing member is secured on a first end to a mounting portion extending from the sleeve and secured on a second end by the collar. The biasing member provides a rotational bias on the sleeve.
The present invention further provides a method of installing a rotary tilt mechanism in a motor vehicle. The rotary tilt mechanism includes a rod disposed within and selectively translatable along a longitudinal axis within a sleeve. The sleeve is rotatably biased around the rod by a biasing member. The tilt mechanism includes a first mounting shaft coupled to an upper steering wheel column member and a second mounting shaft coupled to a lower steering wheel column member. A collar is slid along the longitudinal axis of the sleeve to a predetermined location and engaged to a first end of the biasing member. The collar is then rotated in a direction of increased bias to a location allowing passages in the collar to align with passages on the sleeve and rod, thereby creating a mounting passage. A locking element is advanced along the sleeve to a position precluding the collar from rotating. One of the first and second mounting shafts is inserted through the mounting passage.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limited the scope of the invention.